Chứng minh rằng:

1)B=\(\frac{4}{3}+\frac{10}{9}+\frac{28}{27}+...+\frac{3^{98}+1}{3^{98}}< 100\)

2)C=\(\frac{5}{5.8.11}+\frac{5}{8.11.14}+...+\frac{5}{302.305.308}\)<\(\frac{1}{48}\)

3)D=\(\frac{11}{9}+\frac{18}{16}+\frac{27}{25}+...+\frac{1766}{1764}\)

\(40\frac{20}{43}< D< 40\frac{20}{21}\)

1.____history of England is interesting.

a.an

b.the

c.X

d.a

2.____French were_____first at war with___Germans.

a.the/a/the

b.an/a/the

c.the/the/the

d.X

1.We are finding_____hotel to spend____night.

a.a/the

b.the/the

c.a/a

d.the/a

2.We go to_____church on Sundays.

a.a

b.the

c.an

d.no article

3.Jack went to_____bed early.

a.a

b.an

c.the

d.no article

4.We have..........breakfast at eight.

a.a

b.an

c.the

d.no article

5.He gave us........a good breakfast.

a.a

b.the

c.X

d.an

1.John sat on____chair near_____door.

a.the/a

b.a/the

c.a/a

d.the/the

2.My father comes____home late in the evening.

a.a

b.an

c.no article

d.the

3.____sugar is bad for you teeth.

a.no article

b.an

c.the

d.a

4._____fruits and vegetables are good for you teeth.

a.a

b.an

c.no article

d.the

5.______love is eternal.

a.an

b.a

c.the

d.no article

1.Barbara wasn't wearing a safety-belt, despite regulations.(should)

Barbara___________safety-belt.

2.It was the other driver's fault. He didn't stop at the red light.(should)

He__________at the red light, but he didn't.

3.It's surprising that Barbara's injuries weren't far more serious.(might)

Barbara's injuries_________for more serious.

4.It's surprising how quickly the cuts healed.(might)

The cuts__________far more slowly.

5.I suppose the explanation is that you were very busy.(must)

You__________busy.

1.I'm surprised you didn't visit her after the accident.(should)

Yoy__________after the accident.

2.I can imagine how worried barbara's husband was.(must)

Barbara's husband_______very worried.

3.It's almost certain that someone saw the thief leaving.(must)

Someone__________leaving.

4.In such situations, people often are badly injured or killed.(might)

She__________or killed in the accident.

5.Someone almost certainly broke the window on purpose.(must)

The windown__________on purpose.